Carburetor accelerator pump control apparatus

ABSTRACT

Carburetor accelerator pump control apparatus which varies the stroke of the accelerator pump in response to engine temperature. The control apparatus includes a temperature responsive element which displaces a fulcrum member. As the position of the fulcrum member changes, it varies the stroke of the accelerator pump. Consequently, as the engine compartment temperature increases, the amount of fuel delivered by the accelerator pump is reduced.

Oct. 7, 1975 3251585 5/1966 Derengowski et 26l/34 B 1807,70) 4/]974 261/39 A CARBURETOR ACCELERATOR PUMP CONTROL APPARATUS Suda et al.

R22 742 Ericson 261/34 5 [75] Inventors: Ernest J. ()bermeyer, Jr., Orchard Lake; Robert I. Reed, Detroit, both of Mich.

Primary Examiner-Tim R. Miles Attorney, Agent, or Firm-Roger E1 Erickson; Keith L. Zerschling [73] Assignee: Ford Motor Company Dearhorn,

Mich

ABSTRACT [22] Filed: Apr. 12 1974 [2]] A l. No; 460,655 Carburetor accelerator pump control apparatus which varies the stroke of the accelerator pump in response to engine temperature. The control apparatus includes a temperature responsive element which displaces a fulcrum member As the position of the fulcrum mem- 52 US. 261/34 B; 261 39 A Int. FOZM 7/08 [58} new of 261/34 39 A ber changes, it varies the stroke of the accelerator pump. Consequently. as the engine compartment tem- [56] References perature increases, the amount of fuel delivered by the UNITED STATES PA TENTS accelerator pump is reduced.

Ska 26l/39 A 26U50 AA 3 Claims, 5 Drawing Figures 21354225 9/[958 2,996.05l 8/I96l US. Patent Oct. 7,1975 Sheetl0f3 3,911,061

US Patent 0a. 7,1975 Sheet 2 of 3 3,911,061

M n l. n i m Ill ii W M N M Q /,4\ :11 G N N 4 v I! \.H. 1 l i 4 mm m. w

U.S. Patent 061. 7,1975 Sheet 3 of3 3,911,061

FIG.3

FIG.4

CARBURETOR ACCELERATOR PUMP CONTROL APPARATUS BACKGROUND AND SUMMARY OF THE INVENTION The accelerator pump of a carburetor is generally a mechanical device that supplies extra fuel to the engine simultaneously with the opening of the throttle plates during an acceleration. If the accelerator pump is mechanically linked to the throttle, the pump stroke will be a function of the throttle movement. It is recognized that a cold engine requires a greater rate of fuel delivcry from the accelerator pump than does a warmed engine. lt is also known generally in the art to vary the output of an accelerator pump as a function of temperature. See, for example, U.S. Pat. No. 1981969 granted on Nov. 27, 1934 to A. M. Prentiss.

This invention provides control apparatus for an accelerator pump of an internal combustion engine carburetor that reduces the effective length of the stroke of the accelerator pump in response to increase in engine temperature. The invention also provides accelerator pump control apparatus that is easily incorporated into existing carburetor structure without extensive modification to the basic carburetor housing. Furthermore. this invention provides apparatus that regulates the discharge quantity and rate of the accelerator pump so as to reduce the exhaust emissions ofa warm engine. The invention also provides an accelerator pump control system which is economical to produce and install and which is reliable in service.

Accelerator pump control apparatus constructed in accordance with this invention includes a temperature sensitive means having an element displaceable in response to changes in engine ambient temperature. The temperature sensitive means moves a fulcrum member on which an accelerator pump lever is pivotally mounted. The pivotal connection. between the lever and the fulcrum member. is a pin and slot or track which permits displacement of the fulcrum member relative to the accelerator pump lever to vary the effective length of the lever and. consequently, to vary the stroke and discharge and accelerator pump in response to changes in temperature. The accelerator pump lever is connected by a linkage means to the throttle valve.

BRlEF DESCRIPTlON OF THE DRAWINGS FIG. 1 is a left front clevational view of a portion of a carburetor incorporating the invention.

FIG. 2 is a top view of the accelerator pump control apparatus.

FIG. 3 is a side elevational view taken in the direction of arrow 3 of FIG. 2.

FIG. 4 is a top view of the accelerator pump control lever 29.

FIG. 5 is a top view of the bracket 32.

DESCRIPTION OF A PREFERRED EMBODIMENT Numeral ll refers to a portion of an internal combustion engine carburetor including a main body portion 12 having a fuel bowl l3 and a cover 14. A throttle valve assembly 16 is pivotally positioned in an induction passage 17 of a carburetor and includes a shaft member 18 protruding laterally from the main body portion. Fixed to the end of the throttle shaft is a throttle lever 19. A solenoid 21 is mounted onto the main body of the carburetor and has a movable plunger 22 which acts as an adjustable idle abutment for the throttle lever 19. A second lever means 23 is biased into abutting engagement at point 24 by torsion spring 26. Levers l9 and 23 move simultaneously as though they were a single lever assembly during initial opening movement of the throttle valve. At about half throttle, the lever 23 engages an abutment 27 and lever 19 then moves relative to lever 23 against the force of spring 26 from half throttle position to wide open throttle position.

An accelerator pump 28 is mounted on a wall of the fuel bowl 13, receiving fuel therefrom and injecting the fuel into the induction passages 17 during initial opening movement of the throttle valve assembly. The accelerator pump is actuated by a lever 29 which bears against a spring loaded diaphragm assembly (not shown) at point 31. A bracket 32 is held against the cover of the accelerator pump by threaded fasteners 33. Pivotally mounted to a pin 35 on the bracket 32 is lever 34, one end of which abuts the piston or plunger 36 of a temperature sensitive motor 37. The motor 37 is mounted between a compression spring 38, the base of which abuts a flange 32a on the bracket 32, and a sliding abutment 39. The lever 34 is biased into engagement with the temperature sensitive motor by torsion spring 41. The compression spring 38 is preloaded and significantly stiffer than the torsion spring 41, thus movement of the piston element 36 results in the displacement of the lever 34 rather than in the compression of spring 38.

The temperature sensitive power means 37 in the preferred embodiment is a wax pellet motor similar to that commonly used in cooling system thermostats.

The lever 34 includes an upwardly extending pin 42 which is received within a slot 43 formed in one end of the accelerator pump lever 29. The slot 43 is curved at a radius equal to the distance from the pivot center of lever 34 to the center of the pin 42 and extends in a direction generally parallel to the longitudinal extent of the lever. The opposite end of the accelerator pump lever 29 includes a hole pivotally receiving a link 44 connected to the lever means 23. Movement of the lever 23 will thus be transmitted to the accelerator pump lever by the link 44 causing the accelerator pump lever to pivot about pin 42. A second slot 46 is formed in the accelerator pump lever and receives a pin 47 extending between supports 48 and 49 of the accelerator pump housing 51. The second slot is slightly curved, as shown in FIG. 2, and extends in a direction generally perpendicular to the direction of the first slot 43. The second slot in cooperation with the first slot determines the longitudinal position of the accelerator pump lever relative to the accelerator pump housing.

OPERATION FIGS. 1, 2 and 3 of the drawings show the carburetor elements in cold. idle positions. If the throttle levers are moved clockwise to achieve an acceleration, link mem ber 44 pivots the accelerator pump lever toward the main body of the carburetor about pin 42 positioned within slot 43 as shown in FIGS. 1 and 2 of the drawings. As the ambient air temperature increases, the plunger 36 of the temperature sensitive motor 37 protracts rotating the lever 34 clockwise as viewed in FlG. 2 about pin 35 displacing the pin 42 downwardly according to FIG. 2. As the lever 34 moves clockwise, pin 42 moves toward pin 47 and shortens the effective length of the accelerator pump lever 29. The distance point 31 is displaced for a given displacement of the throttle lever 19 is similarly reduced, Consequently, the discharge of the accelerator pump 28 into the induction passages 17 is decreased in quantity in direct proportion to the increase in ambient air temperature,

Modifications and alterations will occur to those skilled in the art which are included within the scope of the following claims.

We elaimi 1. In an internal combustion engine having a carburetor including an induction passage, a throttle valve pivotally mounted within said induction passage, an accelerator pump to inject fuel into said induction passage, said accelerator pump including an actuating lever, linkage means interconnecting said throttle valve and said actuating lever so that opening movement of said throttle valve results in actuation of the accelerator a temperature sensitive means having an element displaceable in relation to temperature, and a fulcrum member movable in response to displacement of said element of the temperature sensitive means, said fulcrum member including a pivot means, said accelerator pump lever being pivotally attached to said pivot means and movable about said pivot means to discharge fuel from said pump into the induction passage, said accelerator pump lever having a slot formed therein, the pivot means of said fulcrum member comprising a protruding pin, said pin being slidably received within said slot and displaceable along the length of said slot to vary the effective length of said accelerator pump lever, said accelerator pump lever being pivotally connected at one end to said linkage means and at the other end to said pivot means, said accelerator pump lever being connected at an intermediate position to the main housing of the accelerator pump by means of a second pin and slot combination, said first-mentioned slot extending essentially paraL lel to the general longitudinal extent of the accelerator pump lever and said second slot extending generally perpendicular to the direction ofthe firstmentioned slot.

2. In an internal combustion engine having a carburetor including an induction passage, a throttle valve piw otally mounted within said induction passage, an accelerator pump to inject fuel into said induction passage, said accelerator pump including an actuating lever, linkage means interconnecting said throttle valve and said actuating lever so that opening movement of said throttle valve results in actuation of the accelerator a temperature sensitive means having an element displaceable in relation to temperature,

and a fulcrum member movable in response to displacement of said element of the temperature sensitive means, said fulcrum member including a pivot means,

said accelerator pump lever being pivotally attached to said pivot means and movable about said pivot means to discharge fuel from said pump into the induction passage,

said accelerator pump lever having a generally elongate shape,

one end of said lever being pivotally attached to said linkage means,

the other end of said lever including a generally longitudinally extending curved slot, said slot slidably receiving the pivot means of said fulcrum member, said pivot means comprising a pin,

said pin being displaceable along the length of said slot to vary the effective length of said accelerator pump lever,

an intermediate portion of said lever including a second slot extending generally perpendicular to said first slot, said accelerator pump having a housing including a pin slidably received within said second slot,

said intermediate portion of said lever including pro truding means engageable with an adjacent portion of said accelerator pump to actuate said accelerator pump.

3. In an internal combustion engine having a carburetor according to claim 2,

said first-mentioned slot having a radius of curvature centering at the pivot axis of the fulcrum memberv 

1. IN AN INTERNAL COMBUSTION ENGINE HAVING A CARBURETOR INCLUDING AN INDUCTION PASSAGE, A THROTTLE VALVE PIVOTALLY MOUNTED WITHIN SAID INDUCTION PASSAE, AN ACCELERATOR PUMP TO INJECT FUEL INTO SAID INDUCTION PASSAGE, SAID ACCELERATOR PUMP INCLUDING AN ACTUATING LEVER, LINKAGE MEANS INTERCONNECTING SAID THROTTLE VALVE AND SAID ACTUATING LEVER SO HAT OPENING MOVEMENT OF SAID THROTTLE VALVE RESULTS IN ACTUATION OF THE ACCELERATOR PUMP, A TEMPERATURE SENSITIVE MEANS HAVING AN ELEMENT DISPLACEABLE IN RELATION TO TEMPERATURE, AND A FULCRUM MEMBER MOVEABLE IN RESPONSE TO DISPLACEMENT OF SAID ELEMENT OF THE TEMPERATURE SENSITIVE MEANS, SAID FULCRUM MEMBER INCLUDING A PIVOT MEANS, SAID ACCELERATOR PUMP LEVER BEING PIVOTALLY ATTACHED TO SAID PIVOT MEANS AND MOVEABLE ABOUT SAID PIVOT MEANS TO DISCHARGE FUEL FROM SAID PUMP INTO THE INDUCTION PASSAGE, SAID ACCELERATOR PUMP LEVER HAVING A SLOT FORMED THEREIN, THE PIVOT MEANS OF SAID FULCRUM MEMBER COMPRISING A PROTRUDING PIN, SAID PIN BEING SLIDABLY RECEIVED WITHIN SAID SLOT AND DISPLACEABLE ALONE THE LENGTH OF SAID SLOT TO VARY THE EFFECTIVE LENGTH OF SAID ACCELERATOR PUMP LEVER, SAID ACCELERATOR PUMP LEVER BEING PIVOTALLY CONNECTED AT ONE END TO SAID LINKAGE MEANS AND AT THE OTHER END TO SAID PIVOT MEANS, SAID ACCELERATOR PUMP LEVER BEING CONNECTED AT AN INTERMEDIATE POSITION TO THE MAIN HOUSING OF THE ACCELERATOR PUMP BY MEANS OF A SECOND PIN AND SLOT COMBINATION, SAID FIRST-MENTIONED SLOT EXTENDING ESSENTIALLY PARALLEL TO THE GENERAL LONGITUDINAL EXTENT OF THE ACCELERATOR PUMP LEVER AND SAID SECOND SLOT EXTENDING GENERALLY PERPENDICULAR TO THE DIRECTION OF THE FIRST-MENTIONED SLOT.
 2. In an internal combustion engine having a carburetor including an induction passage, a throttle valve pivotally mounted within said induction passage, an accelerator pump to inject fuel into said induction passage, said accelerator pump including an actuating lever, linkage means interconnecting said throttle valve and said actuating lever so that opening movement of said throttle valve results in actuation of the accelerator pump, a temperature sensitive means having an element displaceable in relation to temperature, and a fulcrum member movable in response to displacement of said element of the temperature sensitive means, said fulcrum member including a pivot means, said accelerator pump lever being pivotally attached to said pivot means and movable about said pivot means to discharge fuel from said pump into the induction passage, said accelerator pump lever having a generally elongate shape, one end of said lever being pivotally attached to said linkage means, the other end of said lever including a generally longitudinally extending curved slot, said slot slidably receiving the pivot means of said fulcrum member, said pivot means comprising a pin, said pin being displaceable along the length of said slot to vary the effective length of said accelerator pump lever, an intermediate portion of said lever including a second slot extending generally perpendicular to said first slot, said accelerator pump having a housing including a pin slidably received within said second slot, said intermediate portion of said lever including protruding means engageable with an adjacent portion of said accelerator pump to actuate said accelerator pump.
 3. In an internal combustion engine having a carburetor according to claim 2, said first-mentioned slot having a radius of curvature centering at the pivot axis of the fulcrum member. 